Arthritis & Rheumatism, Volume 60,
October 2009 Abstract Supplement

The 2009 ACR/ARHP Annual Scientific Meeting
Philadelphia October 16-21, 2009.

Muscle Interstitial Levels of Pro- and Anti-Inflammatory Cytokines in Polymyalgia Rheumatica: Impact of Short-Term Prednisolone Treatment

Kreiner, Frederik, Langberg, Henning, Galbo, Henrik

Purpose:

The pathophysiology of symptomatic muscle in polymyalgia rheumatica (PMR) is disputed. In this study, interstitial levels of pro- and anti-inflammatory cytokines in symptomatic muscle were measured before and after short-term prednisolone treatment.

Methods:

Twenty patients (12 females and 8 men; age 74±9 years, BMI 24±5 kg/m²) with PMR just diagnosed according to the Chuang criteria (Ann Intern Med 1982;97:672–80) and 20 controls (11 females and 9 men; age 73±5 years; BMI 25±6 kg/m²) were included. Subjects were studied before and after treatment for 14 days with 20 mg prednisolone/day. Interstitial concentrations of various interleukins (IL), IL-1 receptor antagonist (IL-1Ra), tumor necrosis factor-a (TNF-a), and monocyte chemoattractant protein 1 (MCP-1) were measured in aching quadriceps and trapezius muscles using the microdialysis technique. Plasma levels were measured too.

Results:

Prednisolone treatment abolished symptoms in all patients within a few days; erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were normalized at day 14. Controls had normal ESR and CRP before and after treatment. In both patients and controls, the interstitial levels (table) of most cytokines were markedly higher (p<0.05) than in plasma; exceptions were IL-1a, which was lower in both groups, and TNF-a, which did not differ. However, in both studied muscles interstitial concentrations of all cytokines were significantly higher in patients than in controls (table). Furthermore, in patients concentrations were considerably reduced by prednisolone treatment (table).

	Patients		Controls
	Untreated	Treated	Untreated	Treated
IL-1a (pg/ml)
Quadriceps	*16.0 ± 6.1	^#2.05 ± 1.21	2.31 ± 0.87	3.78 ± 1.82
Trapezius	*36.5 ± 7.05	^#5.85 ± 1.38	3.64 ± 1.28	10.38 ± 4.33
IL-1b (pg/ml)
Quadriceps	*2.18 ± 0.79	^#0.29 ± 0.24	0.29 ± 0.07	0.18 ± 0.06
Trapezius	*4.65 ± 0.92	^#0.70 ± 0.24	0.56 ± 0.12	0.40 ± 0.15
IL-1Ra (pg/ml)
Quadriceps	*2133.7 ± 392.0	^#1575.6 ± 408.2	980.3 ± 283.5	853.7 ± 211.2
Trapezius	*1795.7 ± 366.3	^#1188.9 ± 235.3	580.5 ± 120.8	623.1 ± 126.1
IL-6 (pg/ml)
Quadriceps	*2473.1 ± 934.1	^#1245.7 ± 399.3	597.2 ± 108.7	441.3 ± 82.5
Trapezius	*3747.0 ± 1052.2	^#1635.5 ± 686.2	802.9 ± 122.2	717.1 ± 111.4
IL-8 (pg/ml)
Quadriceps	*141.1 ± 21.8	^#94.6 ± 33.3	67.1 ± 17.1	50.8 ± 8.37
Trapezius	*290.2 ± 67.9	254.9 ± 92.0	74.0 ± 17.8	63.8 ± 9.01
TNF-a (pg/ml)
Quadriceps	*0.98 ± 0.16	^#0.59 ± 0.12	0.76 ± 0.18	0.44 ± 0.10
Trapezius	*1.40 ± 0.26	^#0.74 ± 0.11	0.49 ± 0.11	0.56 ± 0.08
MCP-1 (pg/ml)
Quadriceps	*1601.7 ± 310.4	*^#1342.5 ± 297.9	891.5 ± 153.2	622.3 ± 88.9
Trapezius	*2687.7 ± 411.9	*^#1600.3 ± 344.7	853.7 ± 187.1	637.3 ± 71.9
*p<0.05 vs. corresponding controls;^#p<0.05 vs. untreated patients. Data are mean±SE.

Conclusion:

The present study has provided evidence that skeletal muscle contributes to the pathophysiology of PMR, pro- and anti-inflammatory cytokines being produced locally in the aching muscle.

To cite this abstract, please use the following information:
Kreiner, Frederik, Langberg, Henning, Galbo, Henrik; Muscle Interstitial Levels of Pro- and Anti-Inflammatory Cytokines in Polymyalgia Rheumatica: Impact of Short-Term Prednisolone Treatment [abstract]. Arthritis Rheum 2009;60 Suppl 10 :813
DOI: 10.1002/art.25893

Meeting Menu